Fuel cell systems are increasingly being used as a power source in a wide variety of applications. Fuel cell propulsion systems have also been proposed for use in vehicles as a replacement for internal combustion engines. The fuel cells generate electricity that is used to charge batteries and/or to power an electric motor. A solid-polymer-electrolyte fuel cell includes a polymer electrolyte membrane (PEM) that is sandwiched between an anode and a cathode. To produce electricity through an electrochemical reaction, a fuel, commonly hydrogen (H2), but also either methane (CH4) or methanol (CH3OH), is supplied to the anode and an oxidant, such as oxygen (O2) is supplied to the cathode. The source of the oxygen is commonly air.
In a first half-cell reaction, dissociation of the hydrogen (H2) at the anode generates hydrogen protons (H+) and electrons (e−). The membrane is proton conductive and dielectric. As a result, the protons are transported through the membrane. The electrons flow through an electrical load (such as the batteries or the electric motor) that is connected across the membrane. In a second half-cell reaction, oxygen (O2) at the cathode reacts with protons (H+), and electrons (e−) are taken up to form water (H2O).
Bipolar plates are implemented between fuel cells in the fuel cell stack to facilitate the flow of the gaseous reactants for reaction in the fuel cells. The bipolar plates also facilitate coolant flow through the fuel cell stack to regulate a temperature of the fuel cell stack. Traditional bipolar plates include discrete or inter-digitated channels that define the reactant and coolant flow fields. Such channel configurations can induce coolant maldistribution, which results in a non-uniform temperature profile (i.e., temperature variations) across the fuel cell stack. Additionally, bipolar plates are subject to compressive loads and vibration which results in stress. Accordingly, there is a need to provide improved plate design with enhanced performance over the conventional art.